Nutrition: Fats Chapter 11

Trans Fats: Plaque Attack


Trans Fats: Why All the Drama?

The story of trans fat has it all: profit motive, industrial science, a scary health threat and now, perhaps, a happy ending. In the late 19th century, chemists first figured out how to transform a polyunsaturated fat into a strange hybrid through a process called partial hydrogenation. The reason they did this was to enhance certain qualities of the oil. READ MORE

One of the most important “improvements” this process made possible was extended shelf life. Hydrogenated oils did not go rancid as quickly as natural oils and could also be reheated more often without breaking down. And that saved money.

The process made possible the first vegetable shortening, which could be used instead of lard in baking. It also made possible margarine, which could be used instead of butter. Many consumers embraced both. Over time, these modified vegetable oils would actually seem like healthy alternatives to natural fats.

But as is often the case with a gripping, science-gone-wrong story, this industrially-engineered oil eventually revealed a darker and more dangerous side. Researchers became increasingly concerned that once inside the body, trans fats were behaving very strangely, with harmful consequences. They seemed to be even worse for cholesterol levels than saturated fats and they also fueled inflammation, which is associated with a host of chronic conditions. And even small amounts seemed to pack a dangerous punch. A superbad fat. LESS


But just what made a trans fat so dangerous?

Partial hydrogenation adds hydrogen to polyunsaturated oils. It’s called partial because the result is not 100% saturation. But in the process, the usual kinked configuration of the molecule is straightened out. It is this change in geometry that gives the trans fat their special qualities. (Trans fats also occur in very small quantities in meat and dairy products.) READ MORE

Going back to the analogy of construction materials, Katz explains that “these modified trans fats are basically a construction material we’re not supposed to be using at all. Imagine you’re building a house and you get a delivery of stuff you don’t want. The first thing that happens is you leave it lying around for a long time because you’re trying to figure out what to do with it. It’s probably the same with trans fats. And so it sits around and it starts to corrode, it oxidizes. It’s a lot like rust.” The body ends up using the modified materials it has been given, says Katz, but the end result tends to promote inflammation. LESS


How much of the killer fats did we used to eat?

According to the Harvard School of Public Health, “The FDA once estimated that approximately 95% of prepared cookies, 100% of crackers, and 80% of frozen breakfast products contained trans fat.” By the early 1990s, between 4% and 7% of the average American’s intake of fat calories were from trans fats. Researchers measured the trans fat content in restaurant food and found that a single old fashioned cake donut might have 6 grams of trans fat, an order of French fries or chicken pot pie 8 grams, and large combo meals of fried fish, seafood or fries and chicken nuggets could clock in between 14 and 25 grams of trans fat! READ MORE

Ironically, says Katz, this was the same era of food packages that boldly proclaimed “No Tropical Oils!” In 1990 the American Medical Association’s Council on Scientific Affairs had called for clear disclosure of tropical oils because these saturated plant oils were believed to be nearly as bad for health as the animal fats they replaced. LESS


The Trans-Fat Transition

Nutrition Labels
Nearly two decades later, federal lawmakers would require that trans fats be listed on all food labels as of January 1, 2006. Food manufacturers had already begun to respond by reducing or eliminating the use of these fats. Not all foods come with labels, however, such as foods sold in restaurants and bakeries or served in school cafeterias. But city and state governments have joined in the effort to ban trans fats. And the very good news, says Katz, is that trans fats are exiting the food supply. READ MORE

What are the products that still contain trans fats? “You can still find it in some crackers, chips, cereal and granola bars, dessert items, some breads, some spreads, dressings, sauces and processed meats,” says Katz. “But it’s in fewer and fewer products. And as far as frying fast food in shortening, it’s also getting scarce. There are probably still smaller operations and regional chains that may use it because it’s inexpensive, but most of the large chains ones that are under the microscope have eliminated it.”

Check the Label (Twice)

The best way to make sure you are minimizing trans fats in your own diet, says Katz, “is to carefully read the Nutrition Facts panel on food packages.” But also realize these labels are less than perfect. Manufacturers are allowed to claim 0 grams of trans fats as long as there is less than 0.5 grams per serving. The problem is that what some manufacturers have done, notes Katz, “is to shrink the serving size down to the point where there is less than 0.5g per serving and then they can put 0g per serving on the front.”

So check the label for specific ingredients as well. “Look for ‘partially hydrogenated oil’ or ‘vegetable shortening’ in small letters anywhere in the ingredient list and if you see it, step away from the package and nobody will get hurt.”

Also remember that just because a food has 0g trans fats is no guarantee that it is healthy. It might still contain too much sugar, salt, refined carbohydrates or saturated fats and therefore be a poor food choice. LESS

The material on this site is for informational purposes only and is not intended as medical advice. It should not be used to diagnose or treat any medical condition. Consult a licensed medical professional for the diagnosis and treatment of all medical conditions and before starting a new diet or exercise program. If you have a medical emergency, call 911 immediately.